This invention concerns itself with a novel method of deionizing water containing substances which may be toxic or of a valuable nature and reducing these substances to a more concentrated form. If valuable, these substances may be recovered by further processing or, if toxic, they can be reduced to a low volume for disposal.
To deionize waters of low contaminant levels, such as 100 ppm or lower, the use of a fixed-mixed resin bed deionizer is suitable, because said fixed-mixed bed deionizer can be sized to operate for a long period of time before regeneration of the resins become necessary. However, when the time comes for the regeneration, problems occur when existing techniques are used. Among these problems is the separation of the resins into discrete zones in the vessel after which the acid and caustic regenerants are caused to flow exclusively into their respective zones without too much comingling which can lessen the capacity of the resins due to the exhaustion within the vessel if the unwanted caustic or acid contacts complementary resins. Several moving bed ion exchange concepts have been described over the years and all have moved an increment of resin from a loading vessel into regeneration and reuse vessels and replacing the resin in the loading vessel in the same time frame, but these resins were of a single species, and not of two or more species.